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43316044 WVS |
1 | /* |
2 | * watchdog_dev.c | |
3 | * | |
4 | * (c) Copyright 2008-2011 Alan Cox <alan@lxorguk.ukuu.org.uk>, | |
5 | * All Rights Reserved. | |
6 | * | |
7 | * (c) Copyright 2008-2011 Wim Van Sebroeck <wim@iguana.be>. | |
8 | * | |
9 | * | |
10 | * This source code is part of the generic code that can be used | |
11 | * by all the watchdog timer drivers. | |
12 | * | |
13 | * This part of the generic code takes care of the following | |
14 | * misc device: /dev/watchdog. | |
15 | * | |
16 | * Based on source code of the following authors: | |
17 | * Matt Domsch <Matt_Domsch@dell.com>, | |
18 | * Rob Radez <rob@osinvestor.com>, | |
19 | * Rusty Lynch <rusty@linux.co.intel.com> | |
20 | * Satyam Sharma <satyam@infradead.org> | |
21 | * Randy Dunlap <randy.dunlap@oracle.com> | |
22 | * | |
23 | * This program is free software; you can redistribute it and/or | |
24 | * modify it under the terms of the GNU General Public License | |
25 | * as published by the Free Software Foundation; either version | |
26 | * 2 of the License, or (at your option) any later version. | |
27 | * | |
28 | * Neither Alan Cox, CymruNet Ltd., Wim Van Sebroeck nor Iguana vzw. | |
29 | * admit liability nor provide warranty for any of this software. | |
30 | * This material is provided "AS-IS" and at no charge. | |
31 | */ | |
32 | ||
33 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
34 | ||
b4ffb190 | 35 | #include <linux/cdev.h> /* For character device */ |
43316044 | 36 | #include <linux/errno.h> /* For the -ENODEV/... values */ |
43316044 | 37 | #include <linux/fs.h> /* For file operations */ |
43316044 | 38 | #include <linux/init.h> /* For __init/__exit/... */ |
664a3923 | 39 | #include <linux/jiffies.h> /* For timeout functions */ |
b4ffb190 GR |
40 | #include <linux/kernel.h> /* For printk/panic/... */ |
41 | #include <linux/kref.h> /* For data references */ | |
42 | #include <linux/miscdevice.h> /* For handling misc devices */ | |
43 | #include <linux/module.h> /* For module stuff/... */ | |
44 | #include <linux/mutex.h> /* For mutexes */ | |
44ea3942 | 45 | #include <linux/reboot.h> /* For reboot notifier */ |
b4ffb190 GR |
46 | #include <linux/slab.h> /* For memory functions */ |
47 | #include <linux/types.h> /* For standard types (like size_t) */ | |
48 | #include <linux/watchdog.h> /* For watchdog specific items */ | |
664a3923 | 49 | #include <linux/workqueue.h> /* For workqueue */ |
43316044 WVS |
50 | #include <linux/uaccess.h> /* For copy_to_user/put_user/... */ |
51 | ||
6cfb5aa8 | 52 | #include "watchdog_core.h" |
ff84136c | 53 | #include "watchdog_pretimeout.h" |
09a46e73 | 54 | |
b4ffb190 GR |
55 | /* |
56 | * struct watchdog_core_data - watchdog core internal data | |
57 | * @kref: Reference count. | |
58 | * @cdev: The watchdog's Character device. | |
59 | * @wdd: Pointer to watchdog device. | |
60 | * @lock: Lock for watchdog core. | |
61 | * @status: Watchdog core internal status bits. | |
62 | */ | |
63 | struct watchdog_core_data { | |
64 | struct kref kref; | |
65 | struct cdev cdev; | |
66 | struct watchdog_device *wdd; | |
67 | struct mutex lock; | |
664a3923 | 68 | unsigned long last_keepalive; |
15013ad8 | 69 | unsigned long last_hw_keepalive; |
664a3923 | 70 | struct delayed_work work; |
b4ffb190 GR |
71 | unsigned long status; /* Internal status bits */ |
72 | #define _WDOG_DEV_OPEN 0 /* Opened ? */ | |
73 | #define _WDOG_ALLOW_RELEASE 1 /* Did we receive the magic char ? */ | |
90b826f1 | 74 | #define _WDOG_KEEPALIVE 2 /* Did we receive a keepalive ? */ |
b4ffb190 GR |
75 | }; |
76 | ||
45f5fed3 AC |
77 | /* the dev_t structure to store the dynamically allocated watchdog devices */ |
78 | static dev_t watchdog_devt; | |
b4ffb190 GR |
79 | /* Reference to watchdog device behind /dev/watchdog */ |
80 | static struct watchdog_core_data *old_wd_data; | |
43316044 | 81 | |
664a3923 GR |
82 | static struct workqueue_struct *watchdog_wq; |
83 | ||
2501b015 SR |
84 | static bool handle_boot_enabled = |
85 | IS_ENABLED(CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED); | |
86 | ||
664a3923 GR |
87 | static inline bool watchdog_need_worker(struct watchdog_device *wdd) |
88 | { | |
89 | /* All variables in milli-seconds */ | |
90 | unsigned int hm = wdd->max_hw_heartbeat_ms; | |
91 | unsigned int t = wdd->timeout * 1000; | |
92 | ||
93 | /* | |
94 | * A worker to generate heartbeat requests is needed if all of the | |
95 | * following conditions are true. | |
96 | * - Userspace activated the watchdog. | |
97 | * - The driver provided a value for the maximum hardware timeout, and | |
98 | * thus is aware that the framework supports generating heartbeat | |
99 | * requests. | |
100 | * - Userspace requests a longer timeout than the hardware can handle. | |
3fbfe926 RV |
101 | * |
102 | * Alternatively, if userspace has not opened the watchdog | |
103 | * device, we take care of feeding the watchdog if it is | |
104 | * running. | |
664a3923 | 105 | */ |
3fbfe926 RV |
106 | return (hm && watchdog_active(wdd) && t > hm) || |
107 | (t && !watchdog_active(wdd) && watchdog_hw_running(wdd)); | |
664a3923 GR |
108 | } |
109 | ||
110 | static long watchdog_next_keepalive(struct watchdog_device *wdd) | |
111 | { | |
112 | struct watchdog_core_data *wd_data = wdd->wd_data; | |
113 | unsigned int timeout_ms = wdd->timeout * 1000; | |
114 | unsigned long keepalive_interval; | |
115 | unsigned long last_heartbeat; | |
116 | unsigned long virt_timeout; | |
117 | unsigned int hw_heartbeat_ms; | |
118 | ||
119 | virt_timeout = wd_data->last_keepalive + msecs_to_jiffies(timeout_ms); | |
3fbfe926 | 120 | hw_heartbeat_ms = min_not_zero(timeout_ms, wdd->max_hw_heartbeat_ms); |
664a3923 GR |
121 | keepalive_interval = msecs_to_jiffies(hw_heartbeat_ms / 2); |
122 | ||
ee142889 GR |
123 | if (!watchdog_active(wdd)) |
124 | return keepalive_interval; | |
125 | ||
664a3923 GR |
126 | /* |
127 | * To ensure that the watchdog times out wdd->timeout seconds | |
128 | * after the most recent ping from userspace, the last | |
129 | * worker ping has to come in hw_heartbeat_ms before this timeout. | |
130 | */ | |
131 | last_heartbeat = virt_timeout - msecs_to_jiffies(hw_heartbeat_ms); | |
132 | return min_t(long, last_heartbeat - jiffies, keepalive_interval); | |
133 | } | |
134 | ||
135 | static inline void watchdog_update_worker(struct watchdog_device *wdd) | |
136 | { | |
137 | struct watchdog_core_data *wd_data = wdd->wd_data; | |
138 | ||
139 | if (watchdog_need_worker(wdd)) { | |
140 | long t = watchdog_next_keepalive(wdd); | |
141 | ||
142 | if (t > 0) | |
143 | mod_delayed_work(watchdog_wq, &wd_data->work, t); | |
144 | } else { | |
145 | cancel_delayed_work(&wd_data->work); | |
146 | } | |
147 | } | |
148 | ||
149 | static int __watchdog_ping(struct watchdog_device *wdd) | |
150 | { | |
15013ad8 GR |
151 | struct watchdog_core_data *wd_data = wdd->wd_data; |
152 | unsigned long earliest_keepalive = wd_data->last_hw_keepalive + | |
153 | msecs_to_jiffies(wdd->min_hw_heartbeat_ms); | |
664a3923 GR |
154 | int err; |
155 | ||
15013ad8 GR |
156 | if (time_is_after_jiffies(earliest_keepalive)) { |
157 | mod_delayed_work(watchdog_wq, &wd_data->work, | |
158 | earliest_keepalive - jiffies); | |
159 | return 0; | |
160 | } | |
161 | ||
162 | wd_data->last_hw_keepalive = jiffies; | |
163 | ||
664a3923 GR |
164 | if (wdd->ops->ping) |
165 | err = wdd->ops->ping(wdd); /* ping the watchdog */ | |
166 | else | |
167 | err = wdd->ops->start(wdd); /* restart watchdog */ | |
168 | ||
169 | watchdog_update_worker(wdd); | |
170 | ||
171 | return err; | |
172 | } | |
173 | ||
43316044 WVS |
174 | /* |
175 | * watchdog_ping: ping the watchdog. | |
bc794ac3 | 176 | * @wdd: the watchdog device to ping |
43316044 | 177 | * |
b4ffb190 GR |
178 | * The caller must hold wd_data->lock. |
179 | * | |
43316044 WVS |
180 | * If the watchdog has no own ping operation then it needs to be |
181 | * restarted via the start operation. This wrapper function does | |
182 | * exactly that. | |
234445b4 | 183 | * We only ping when the watchdog device is running. |
43316044 WVS |
184 | */ |
185 | ||
bc794ac3 | 186 | static int watchdog_ping(struct watchdog_device *wdd) |
43316044 | 187 | { |
664a3923 | 188 | struct watchdog_core_data *wd_data = wdd->wd_data; |
e907df32 | 189 | |
ee142889 | 190 | if (!watchdog_active(wdd) && !watchdog_hw_running(wdd)) |
b4ffb190 | 191 | return 0; |
7a879824 | 192 | |
90b826f1 GR |
193 | set_bit(_WDOG_KEEPALIVE, &wd_data->status); |
194 | ||
664a3923 GR |
195 | wd_data->last_keepalive = jiffies; |
196 | return __watchdog_ping(wdd); | |
197 | } | |
7a879824 | 198 | |
c013b65a RV |
199 | static bool watchdog_worker_should_ping(struct watchdog_core_data *wd_data) |
200 | { | |
201 | struct watchdog_device *wdd = wd_data->wdd; | |
202 | ||
203 | return wdd && (watchdog_active(wdd) || watchdog_hw_running(wdd)); | |
204 | } | |
205 | ||
664a3923 GR |
206 | static void watchdog_ping_work(struct work_struct *work) |
207 | { | |
208 | struct watchdog_core_data *wd_data; | |
664a3923 GR |
209 | |
210 | wd_data = container_of(to_delayed_work(work), struct watchdog_core_data, | |
211 | work); | |
212 | ||
213 | mutex_lock(&wd_data->lock); | |
c013b65a RV |
214 | if (watchdog_worker_should_ping(wd_data)) |
215 | __watchdog_ping(wd_data->wdd); | |
664a3923 | 216 | mutex_unlock(&wd_data->lock); |
234445b4 WVS |
217 | } |
218 | ||
219 | /* | |
220 | * watchdog_start: wrapper to start the watchdog. | |
bc794ac3 | 221 | * @wdd: the watchdog device to start |
234445b4 | 222 | * |
b4ffb190 GR |
223 | * The caller must hold wd_data->lock. |
224 | * | |
234445b4 WVS |
225 | * Start the watchdog if it is not active and mark it active. |
226 | * This function returns zero on success or a negative errno code for | |
227 | * failure. | |
228 | */ | |
229 | ||
bc794ac3 | 230 | static int watchdog_start(struct watchdog_device *wdd) |
234445b4 | 231 | { |
664a3923 GR |
232 | struct watchdog_core_data *wd_data = wdd->wd_data; |
233 | unsigned long started_at; | |
b4ffb190 | 234 | int err; |
e907df32 | 235 | |
bc794ac3 | 236 | if (watchdog_active(wdd)) |
b4ffb190 | 237 | return 0; |
234445b4 | 238 | |
90b826f1 GR |
239 | set_bit(_WDOG_KEEPALIVE, &wd_data->status); |
240 | ||
664a3923 | 241 | started_at = jiffies; |
ee142889 GR |
242 | if (watchdog_hw_running(wdd) && wdd->ops->ping) |
243 | err = wdd->ops->ping(wdd); | |
244 | else | |
245 | err = wdd->ops->start(wdd); | |
664a3923 | 246 | if (err == 0) { |
bc794ac3 | 247 | set_bit(WDOG_ACTIVE, &wdd->status); |
664a3923 GR |
248 | wd_data->last_keepalive = started_at; |
249 | watchdog_update_worker(wdd); | |
250 | } | |
7a879824 | 251 | |
7a879824 | 252 | return err; |
234445b4 WVS |
253 | } |
254 | ||
255 | /* | |
256 | * watchdog_stop: wrapper to stop the watchdog. | |
bc794ac3 | 257 | * @wdd: the watchdog device to stop |
234445b4 | 258 | * |
b4ffb190 GR |
259 | * The caller must hold wd_data->lock. |
260 | * | |
234445b4 WVS |
261 | * Stop the watchdog if it is still active and unmark it active. |
262 | * This function returns zero on success or a negative errno code for | |
263 | * failure. | |
7e192b9c | 264 | * If the 'nowayout' feature was set, the watchdog cannot be stopped. |
234445b4 WVS |
265 | */ |
266 | ||
bc794ac3 | 267 | static int watchdog_stop(struct watchdog_device *wdd) |
234445b4 | 268 | { |
ee142889 | 269 | int err = 0; |
e907df32 | 270 | |
bc794ac3 | 271 | if (!watchdog_active(wdd)) |
b4ffb190 | 272 | return 0; |
7e192b9c | 273 | |
bc794ac3 | 274 | if (test_bit(WDOG_NO_WAY_OUT, &wdd->status)) { |
0254e953 GR |
275 | pr_info("watchdog%d: nowayout prevents watchdog being stopped!\n", |
276 | wdd->id); | |
b4ffb190 | 277 | return -EBUSY; |
7e192b9c | 278 | } |
234445b4 | 279 | |
3c10bbde GR |
280 | if (wdd->ops->stop) { |
281 | clear_bit(WDOG_HW_RUNNING, &wdd->status); | |
d0684c8a | 282 | err = wdd->ops->stop(wdd); |
3c10bbde | 283 | } else { |
d0684c8a | 284 | set_bit(WDOG_HW_RUNNING, &wdd->status); |
3c10bbde | 285 | } |
d0684c8a | 286 | |
664a3923 | 287 | if (err == 0) { |
bc794ac3 | 288 | clear_bit(WDOG_ACTIVE, &wdd->status); |
ee142889 | 289 | watchdog_update_worker(wdd); |
664a3923 | 290 | } |
7a879824 | 291 | |
7a879824 HG |
292 | return err; |
293 | } | |
294 | ||
295 | /* | |
296 | * watchdog_get_status: wrapper to get the watchdog status | |
bc794ac3 | 297 | * @wdd: the watchdog device to get the status from |
b4ffb190 GR |
298 | * |
299 | * The caller must hold wd_data->lock. | |
7a879824 HG |
300 | * |
301 | * Get the watchdog's status flags. | |
302 | */ | |
303 | ||
b4ffb190 | 304 | static unsigned int watchdog_get_status(struct watchdog_device *wdd) |
7a879824 | 305 | { |
90b826f1 GR |
306 | struct watchdog_core_data *wd_data = wdd->wd_data; |
307 | unsigned int status; | |
7a879824 | 308 | |
90b826f1 GR |
309 | if (wdd->ops->status) |
310 | status = wdd->ops->status(wdd); | |
311 | else | |
312 | status = wdd->bootstatus & (WDIOF_CARDRESET | | |
313 | WDIOF_OVERHEAT | | |
314 | WDIOF_FANFAULT | | |
315 | WDIOF_EXTERN1 | | |
316 | WDIOF_EXTERN2 | | |
317 | WDIOF_POWERUNDER | | |
318 | WDIOF_POWEROVER); | |
319 | ||
320 | if (test_bit(_WDOG_ALLOW_RELEASE, &wd_data->status)) | |
321 | status |= WDIOF_MAGICCLOSE; | |
322 | ||
323 | if (test_and_clear_bit(_WDOG_KEEPALIVE, &wd_data->status)) | |
324 | status |= WDIOF_KEEPALIVEPING; | |
325 | ||
326 | return status; | |
7a879824 HG |
327 | } |
328 | ||
329 | /* | |
330 | * watchdog_set_timeout: set the watchdog timer timeout | |
bc794ac3 | 331 | * @wdd: the watchdog device to set the timeout for |
7a879824 | 332 | * @timeout: timeout to set in seconds |
b4ffb190 GR |
333 | * |
334 | * The caller must hold wd_data->lock. | |
7a879824 HG |
335 | */ |
336 | ||
bc794ac3 | 337 | static int watchdog_set_timeout(struct watchdog_device *wdd, |
7a879824 HG |
338 | unsigned int timeout) |
339 | { | |
fb32e9b9 GR |
340 | int err = 0; |
341 | ||
342 | if (!(wdd->info->options & WDIOF_SETTIMEOUT)) | |
7a879824 HG |
343 | return -EOPNOTSUPP; |
344 | ||
bc794ac3 | 345 | if (watchdog_timeout_invalid(wdd, timeout)) |
7a879824 HG |
346 | return -EINVAL; |
347 | ||
df044e02 | 348 | if (wdd->ops->set_timeout) { |
fb32e9b9 | 349 | err = wdd->ops->set_timeout(wdd, timeout); |
df044e02 | 350 | } else { |
fb32e9b9 | 351 | wdd->timeout = timeout; |
df044e02 WS |
352 | /* Disable pretimeout if it doesn't fit the new timeout */ |
353 | if (wdd->pretimeout >= wdd->timeout) | |
354 | wdd->pretimeout = 0; | |
355 | } | |
fb32e9b9 | 356 | |
664a3923 GR |
357 | watchdog_update_worker(wdd); |
358 | ||
fb32e9b9 | 359 | return err; |
7a879824 HG |
360 | } |
361 | ||
df044e02 WS |
362 | /* |
363 | * watchdog_set_pretimeout: set the watchdog timer pretimeout | |
364 | * @wdd: the watchdog device to set the timeout for | |
365 | * @timeout: pretimeout to set in seconds | |
366 | */ | |
367 | ||
368 | static int watchdog_set_pretimeout(struct watchdog_device *wdd, | |
369 | unsigned int timeout) | |
370 | { | |
371 | int err = 0; | |
372 | ||
373 | if (!(wdd->info->options & WDIOF_PRETIMEOUT)) | |
374 | return -EOPNOTSUPP; | |
375 | ||
376 | if (watchdog_pretimeout_invalid(wdd, timeout)) | |
377 | return -EINVAL; | |
378 | ||
379 | if (wdd->ops->set_pretimeout) | |
380 | err = wdd->ops->set_pretimeout(wdd, timeout); | |
381 | else | |
382 | wdd->pretimeout = timeout; | |
383 | ||
384 | return err; | |
385 | } | |
386 | ||
7a879824 HG |
387 | /* |
388 | * watchdog_get_timeleft: wrapper to get the time left before a reboot | |
bc794ac3 | 389 | * @wdd: the watchdog device to get the remaining time from |
7a879824 HG |
390 | * @timeleft: the time that's left |
391 | * | |
b4ffb190 GR |
392 | * The caller must hold wd_data->lock. |
393 | * | |
7a879824 HG |
394 | * Get the time before a watchdog will reboot (if not pinged). |
395 | */ | |
396 | ||
bc794ac3 | 397 | static int watchdog_get_timeleft(struct watchdog_device *wdd, |
7a879824 HG |
398 | unsigned int *timeleft) |
399 | { | |
7a879824 | 400 | *timeleft = 0; |
b4ffb190 | 401 | |
bc794ac3 | 402 | if (!wdd->ops->get_timeleft) |
7a879824 HG |
403 | return -EOPNOTSUPP; |
404 | ||
bc794ac3 | 405 | *timeleft = wdd->ops->get_timeleft(wdd); |
7a879824 | 406 | |
b4ffb190 | 407 | return 0; |
7a879824 HG |
408 | } |
409 | ||
33b71126 PA |
410 | #ifdef CONFIG_WATCHDOG_SYSFS |
411 | static ssize_t nowayout_show(struct device *dev, struct device_attribute *attr, | |
412 | char *buf) | |
413 | { | |
414 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
415 | ||
416 | return sprintf(buf, "%d\n", !!test_bit(WDOG_NO_WAY_OUT, &wdd->status)); | |
417 | } | |
418 | static DEVICE_ATTR_RO(nowayout); | |
419 | ||
420 | static ssize_t status_show(struct device *dev, struct device_attribute *attr, | |
421 | char *buf) | |
422 | { | |
423 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
b4ffb190 GR |
424 | struct watchdog_core_data *wd_data = wdd->wd_data; |
425 | unsigned int status; | |
33b71126 | 426 | |
b4ffb190 GR |
427 | mutex_lock(&wd_data->lock); |
428 | status = watchdog_get_status(wdd); | |
429 | mutex_unlock(&wd_data->lock); | |
33b71126 | 430 | |
90b826f1 | 431 | return sprintf(buf, "0x%x\n", status); |
33b71126 PA |
432 | } |
433 | static DEVICE_ATTR_RO(status); | |
434 | ||
435 | static ssize_t bootstatus_show(struct device *dev, | |
436 | struct device_attribute *attr, char *buf) | |
437 | { | |
438 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
439 | ||
440 | return sprintf(buf, "%u\n", wdd->bootstatus); | |
441 | } | |
442 | static DEVICE_ATTR_RO(bootstatus); | |
443 | ||
444 | static ssize_t timeleft_show(struct device *dev, struct device_attribute *attr, | |
445 | char *buf) | |
446 | { | |
447 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
b4ffb190 | 448 | struct watchdog_core_data *wd_data = wdd->wd_data; |
33b71126 PA |
449 | ssize_t status; |
450 | unsigned int val; | |
451 | ||
b4ffb190 | 452 | mutex_lock(&wd_data->lock); |
33b71126 | 453 | status = watchdog_get_timeleft(wdd, &val); |
b4ffb190 | 454 | mutex_unlock(&wd_data->lock); |
33b71126 PA |
455 | if (!status) |
456 | status = sprintf(buf, "%u\n", val); | |
457 | ||
458 | return status; | |
459 | } | |
460 | static DEVICE_ATTR_RO(timeleft); | |
461 | ||
462 | static ssize_t timeout_show(struct device *dev, struct device_attribute *attr, | |
463 | char *buf) | |
464 | { | |
465 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
466 | ||
467 | return sprintf(buf, "%u\n", wdd->timeout); | |
468 | } | |
469 | static DEVICE_ATTR_RO(timeout); | |
470 | ||
df044e02 WS |
471 | static ssize_t pretimeout_show(struct device *dev, |
472 | struct device_attribute *attr, char *buf) | |
473 | { | |
474 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
475 | ||
476 | return sprintf(buf, "%u\n", wdd->pretimeout); | |
477 | } | |
478 | static DEVICE_ATTR_RO(pretimeout); | |
479 | ||
33b71126 PA |
480 | static ssize_t identity_show(struct device *dev, struct device_attribute *attr, |
481 | char *buf) | |
482 | { | |
483 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
484 | ||
485 | return sprintf(buf, "%s\n", wdd->info->identity); | |
486 | } | |
487 | static DEVICE_ATTR_RO(identity); | |
488 | ||
489 | static ssize_t state_show(struct device *dev, struct device_attribute *attr, | |
490 | char *buf) | |
491 | { | |
492 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
493 | ||
494 | if (watchdog_active(wdd)) | |
495 | return sprintf(buf, "active\n"); | |
496 | ||
497 | return sprintf(buf, "inactive\n"); | |
498 | } | |
499 | static DEVICE_ATTR_RO(state); | |
500 | ||
89873a71 VZ |
501 | static ssize_t pretimeout_available_governors_show(struct device *dev, |
502 | struct device_attribute *attr, char *buf) | |
503 | { | |
504 | return watchdog_pretimeout_available_governors_get(buf); | |
505 | } | |
506 | static DEVICE_ATTR_RO(pretimeout_available_governors); | |
507 | ||
ff84136c VZ |
508 | static ssize_t pretimeout_governor_show(struct device *dev, |
509 | struct device_attribute *attr, | |
510 | char *buf) | |
511 | { | |
512 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
513 | ||
514 | return watchdog_pretimeout_governor_get(wdd, buf); | |
515 | } | |
53f96cee VZ |
516 | |
517 | static ssize_t pretimeout_governor_store(struct device *dev, | |
518 | struct device_attribute *attr, | |
519 | const char *buf, size_t count) | |
520 | { | |
521 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
522 | int ret = watchdog_pretimeout_governor_set(wdd, buf); | |
523 | ||
524 | if (!ret) | |
525 | ret = count; | |
526 | ||
527 | return ret; | |
528 | } | |
529 | static DEVICE_ATTR_RW(pretimeout_governor); | |
ff84136c | 530 | |
33b71126 PA |
531 | static umode_t wdt_is_visible(struct kobject *kobj, struct attribute *attr, |
532 | int n) | |
533 | { | |
534 | struct device *dev = container_of(kobj, struct device, kobj); | |
535 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
536 | umode_t mode = attr->mode; | |
537 | ||
90b826f1 | 538 | if (attr == &dev_attr_timeleft.attr && !wdd->ops->get_timeleft) |
33b71126 | 539 | mode = 0; |
df044e02 WS |
540 | else if (attr == &dev_attr_pretimeout.attr && |
541 | !(wdd->info->options & WDIOF_PRETIMEOUT)) | |
542 | mode = 0; | |
89873a71 VZ |
543 | else if ((attr == &dev_attr_pretimeout_governor.attr || |
544 | attr == &dev_attr_pretimeout_available_governors.attr) && | |
ff84136c VZ |
545 | (!(wdd->info->options & WDIOF_PRETIMEOUT) || |
546 | !IS_ENABLED(CONFIG_WATCHDOG_PRETIMEOUT_GOV))) | |
547 | mode = 0; | |
33b71126 PA |
548 | |
549 | return mode; | |
550 | } | |
551 | static struct attribute *wdt_attrs[] = { | |
552 | &dev_attr_state.attr, | |
553 | &dev_attr_identity.attr, | |
554 | &dev_attr_timeout.attr, | |
df044e02 | 555 | &dev_attr_pretimeout.attr, |
33b71126 PA |
556 | &dev_attr_timeleft.attr, |
557 | &dev_attr_bootstatus.attr, | |
558 | &dev_attr_status.attr, | |
559 | &dev_attr_nowayout.attr, | |
ff84136c | 560 | &dev_attr_pretimeout_governor.attr, |
89873a71 | 561 | &dev_attr_pretimeout_available_governors.attr, |
33b71126 PA |
562 | NULL, |
563 | }; | |
564 | ||
565 | static const struct attribute_group wdt_group = { | |
566 | .attrs = wdt_attrs, | |
567 | .is_visible = wdt_is_visible, | |
568 | }; | |
569 | __ATTRIBUTE_GROUPS(wdt); | |
570 | #else | |
571 | #define wdt_groups NULL | |
572 | #endif | |
573 | ||
7a879824 HG |
574 | /* |
575 | * watchdog_ioctl_op: call the watchdog drivers ioctl op if defined | |
bc794ac3 | 576 | * @wdd: the watchdog device to do the ioctl on |
7a879824 HG |
577 | * @cmd: watchdog command |
578 | * @arg: argument pointer | |
b4ffb190 GR |
579 | * |
580 | * The caller must hold wd_data->lock. | |
7a879824 HG |
581 | */ |
582 | ||
bc794ac3 | 583 | static int watchdog_ioctl_op(struct watchdog_device *wdd, unsigned int cmd, |
7a879824 HG |
584 | unsigned long arg) |
585 | { | |
bc794ac3 | 586 | if (!wdd->ops->ioctl) |
7a879824 HG |
587 | return -ENOIOCTLCMD; |
588 | ||
b4ffb190 | 589 | return wdd->ops->ioctl(wdd, cmd, arg); |
43316044 WVS |
590 | } |
591 | ||
592 | /* | |
593 | * watchdog_write: writes to the watchdog. | |
594 | * @file: file from VFS | |
595 | * @data: user address of data | |
596 | * @len: length of data | |
597 | * @ppos: pointer to the file offset | |
598 | * | |
599 | * A write to a watchdog device is defined as a keepalive ping. | |
017cf080 | 600 | * Writing the magic 'V' sequence allows the next close to turn |
7e192b9c | 601 | * off the watchdog (if 'nowayout' is not set). |
43316044 WVS |
602 | */ |
603 | ||
604 | static ssize_t watchdog_write(struct file *file, const char __user *data, | |
605 | size_t len, loff_t *ppos) | |
606 | { | |
b4ffb190 GR |
607 | struct watchdog_core_data *wd_data = file->private_data; |
608 | struct watchdog_device *wdd; | |
609 | int err; | |
43316044 WVS |
610 | size_t i; |
611 | char c; | |
612 | ||
613 | if (len == 0) | |
614 | return 0; | |
615 | ||
017cf080 WVS |
616 | /* |
617 | * Note: just in case someone wrote the magic character | |
618 | * five months ago... | |
619 | */ | |
b4ffb190 | 620 | clear_bit(_WDOG_ALLOW_RELEASE, &wd_data->status); |
017cf080 WVS |
621 | |
622 | /* scan to see whether or not we got the magic character */ | |
43316044 WVS |
623 | for (i = 0; i != len; i++) { |
624 | if (get_user(c, data + i)) | |
625 | return -EFAULT; | |
017cf080 | 626 | if (c == 'V') |
b4ffb190 | 627 | set_bit(_WDOG_ALLOW_RELEASE, &wd_data->status); |
43316044 WVS |
628 | } |
629 | ||
630 | /* someone wrote to us, so we send the watchdog a keepalive ping */ | |
b4ffb190 GR |
631 | |
632 | err = -ENODEV; | |
633 | mutex_lock(&wd_data->lock); | |
634 | wdd = wd_data->wdd; | |
635 | if (wdd) | |
636 | err = watchdog_ping(wdd); | |
637 | mutex_unlock(&wd_data->lock); | |
638 | ||
5ef79663 AU |
639 | if (err < 0) |
640 | return err; | |
43316044 WVS |
641 | |
642 | return len; | |
643 | } | |
644 | ||
2fa03560 WVS |
645 | /* |
646 | * watchdog_ioctl: handle the different ioctl's for the watchdog device. | |
647 | * @file: file handle to the device | |
648 | * @cmd: watchdog command | |
649 | * @arg: argument pointer | |
650 | * | |
651 | * The watchdog API defines a common set of functions for all watchdogs | |
652 | * according to their available features. | |
653 | */ | |
654 | ||
655 | static long watchdog_ioctl(struct file *file, unsigned int cmd, | |
656 | unsigned long arg) | |
657 | { | |
b4ffb190 | 658 | struct watchdog_core_data *wd_data = file->private_data; |
2fa03560 | 659 | void __user *argp = (void __user *)arg; |
b4ffb190 | 660 | struct watchdog_device *wdd; |
2fa03560 WVS |
661 | int __user *p = argp; |
662 | unsigned int val; | |
234445b4 | 663 | int err; |
2fa03560 | 664 | |
b4ffb190 GR |
665 | mutex_lock(&wd_data->lock); |
666 | ||
667 | wdd = wd_data->wdd; | |
668 | if (!wdd) { | |
669 | err = -ENODEV; | |
670 | goto out_ioctl; | |
671 | } | |
672 | ||
7a879824 HG |
673 | err = watchdog_ioctl_op(wdd, cmd, arg); |
674 | if (err != -ENOIOCTLCMD) | |
b4ffb190 | 675 | goto out_ioctl; |
78d88fc0 | 676 | |
2fa03560 WVS |
677 | switch (cmd) { |
678 | case WDIOC_GETSUPPORT: | |
b4ffb190 | 679 | err = copy_to_user(argp, wdd->info, |
2fa03560 | 680 | sizeof(struct watchdog_info)) ? -EFAULT : 0; |
b4ffb190 | 681 | break; |
2fa03560 | 682 | case WDIOC_GETSTATUS: |
b4ffb190 GR |
683 | val = watchdog_get_status(wdd); |
684 | err = put_user(val, p); | |
685 | break; | |
2fa03560 | 686 | case WDIOC_GETBOOTSTATUS: |
b4ffb190 GR |
687 | err = put_user(wdd->bootstatus, p); |
688 | break; | |
234445b4 | 689 | case WDIOC_SETOPTIONS: |
b4ffb190 GR |
690 | if (get_user(val, p)) { |
691 | err = -EFAULT; | |
692 | break; | |
693 | } | |
234445b4 WVS |
694 | if (val & WDIOS_DISABLECARD) { |
695 | err = watchdog_stop(wdd); | |
696 | if (err < 0) | |
b4ffb190 | 697 | break; |
234445b4 | 698 | } |
b4ffb190 | 699 | if (val & WDIOS_ENABLECARD) |
234445b4 | 700 | err = watchdog_start(wdd); |
b4ffb190 | 701 | break; |
c2dc00e4 | 702 | case WDIOC_KEEPALIVE: |
b4ffb190 GR |
703 | if (!(wdd->info->options & WDIOF_KEEPALIVEPING)) { |
704 | err = -EOPNOTSUPP; | |
705 | break; | |
706 | } | |
707 | err = watchdog_ping(wdd); | |
708 | break; | |
014d694e | 709 | case WDIOC_SETTIMEOUT: |
b4ffb190 GR |
710 | if (get_user(val, p)) { |
711 | err = -EFAULT; | |
712 | break; | |
713 | } | |
7a879824 | 714 | err = watchdog_set_timeout(wdd, val); |
014d694e | 715 | if (err < 0) |
b4ffb190 | 716 | break; |
014d694e WVS |
717 | /* If the watchdog is active then we send a keepalive ping |
718 | * to make sure that the watchdog keep's running (and if | |
719 | * possible that it takes the new timeout) */ | |
5ef79663 AU |
720 | err = watchdog_ping(wdd); |
721 | if (err < 0) | |
b4ffb190 | 722 | break; |
e2af3092 | 723 | /* fall through */ |
014d694e WVS |
724 | case WDIOC_GETTIMEOUT: |
725 | /* timeout == 0 means that we don't know the timeout */ | |
b4ffb190 GR |
726 | if (wdd->timeout == 0) { |
727 | err = -EOPNOTSUPP; | |
728 | break; | |
729 | } | |
730 | err = put_user(wdd->timeout, p); | |
731 | break; | |
fd7b673c | 732 | case WDIOC_GETTIMELEFT: |
7a879824 | 733 | err = watchdog_get_timeleft(wdd, &val); |
b4ffb190 GR |
734 | if (err < 0) |
735 | break; | |
736 | err = put_user(val, p); | |
737 | break; | |
df044e02 WS |
738 | case WDIOC_SETPRETIMEOUT: |
739 | if (get_user(val, p)) { | |
740 | err = -EFAULT; | |
741 | break; | |
742 | } | |
743 | err = watchdog_set_pretimeout(wdd, val); | |
744 | break; | |
745 | case WDIOC_GETPRETIMEOUT: | |
746 | err = put_user(wdd->pretimeout, p); | |
747 | break; | |
2fa03560 | 748 | default: |
b4ffb190 GR |
749 | err = -ENOTTY; |
750 | break; | |
2fa03560 | 751 | } |
b4ffb190 GR |
752 | |
753 | out_ioctl: | |
754 | mutex_unlock(&wd_data->lock); | |
755 | return err; | |
2fa03560 WVS |
756 | } |
757 | ||
43316044 | 758 | /* |
45f5fed3 | 759 | * watchdog_open: open the /dev/watchdog* devices. |
43316044 WVS |
760 | * @inode: inode of device |
761 | * @file: file handle to device | |
762 | * | |
45f5fed3 | 763 | * When the /dev/watchdog* device gets opened, we start the watchdog. |
43316044 WVS |
764 | * Watch out: the /dev/watchdog device is single open, so we make sure |
765 | * it can only be opened once. | |
766 | */ | |
767 | ||
768 | static int watchdog_open(struct inode *inode, struct file *file) | |
769 | { | |
b4ffb190 | 770 | struct watchdog_core_data *wd_data; |
45f5fed3 | 771 | struct watchdog_device *wdd; |
4bcd615f | 772 | bool hw_running; |
b4ffb190 | 773 | int err; |
45f5fed3 AC |
774 | |
775 | /* Get the corresponding watchdog device */ | |
776 | if (imajor(inode) == MISC_MAJOR) | |
b4ffb190 | 777 | wd_data = old_wd_data; |
45f5fed3 | 778 | else |
b4ffb190 GR |
779 | wd_data = container_of(inode->i_cdev, struct watchdog_core_data, |
780 | cdev); | |
43316044 WVS |
781 | |
782 | /* the watchdog is single open! */ | |
b4ffb190 | 783 | if (test_and_set_bit(_WDOG_DEV_OPEN, &wd_data->status)) |
43316044 WVS |
784 | return -EBUSY; |
785 | ||
b4ffb190 GR |
786 | wdd = wd_data->wdd; |
787 | ||
43316044 WVS |
788 | /* |
789 | * If the /dev/watchdog device is open, we don't want the module | |
790 | * to be unloaded. | |
791 | */ | |
4bcd615f GR |
792 | hw_running = watchdog_hw_running(wdd); |
793 | if (!hw_running && !try_module_get(wdd->ops->owner)) { | |
b4ffb190 GR |
794 | err = -EBUSY; |
795 | goto out_clear; | |
796 | } | |
43316044 | 797 | |
234445b4 | 798 | err = watchdog_start(wdd); |
43316044 WVS |
799 | if (err < 0) |
800 | goto out_mod; | |
801 | ||
b4ffb190 | 802 | file->private_data = wd_data; |
45f5fed3 | 803 | |
4bcd615f | 804 | if (!hw_running) |
ee142889 | 805 | kref_get(&wd_data->kref); |
e907df32 | 806 | |
43316044 WVS |
807 | /* dev/watchdog is a virtual (and thus non-seekable) filesystem */ |
808 | return nonseekable_open(inode, file); | |
809 | ||
810 | out_mod: | |
b4ffb190 GR |
811 | module_put(wd_data->wdd->ops->owner); |
812 | out_clear: | |
813 | clear_bit(_WDOG_DEV_OPEN, &wd_data->status); | |
43316044 WVS |
814 | return err; |
815 | } | |
816 | ||
b4ffb190 GR |
817 | static void watchdog_core_data_release(struct kref *kref) |
818 | { | |
819 | struct watchdog_core_data *wd_data; | |
820 | ||
821 | wd_data = container_of(kref, struct watchdog_core_data, kref); | |
822 | ||
823 | kfree(wd_data); | |
824 | } | |
825 | ||
43316044 | 826 | /* |
45f5fed3 AC |
827 | * watchdog_release: release the watchdog device. |
828 | * @inode: inode of device | |
829 | * @file: file handle to device | |
43316044 | 830 | * |
017cf080 | 831 | * This is the code for when /dev/watchdog gets closed. We will only |
7e192b9c WVS |
832 | * stop the watchdog when we have received the magic char (and nowayout |
833 | * was not set), else the watchdog will keep running. | |
43316044 WVS |
834 | */ |
835 | ||
836 | static int watchdog_release(struct inode *inode, struct file *file) | |
837 | { | |
b4ffb190 GR |
838 | struct watchdog_core_data *wd_data = file->private_data; |
839 | struct watchdog_device *wdd; | |
017cf080 | 840 | int err = -EBUSY; |
d1ed3ba4 | 841 | bool running; |
017cf080 | 842 | |
b4ffb190 GR |
843 | mutex_lock(&wd_data->lock); |
844 | ||
845 | wdd = wd_data->wdd; | |
846 | if (!wdd) | |
847 | goto done; | |
848 | ||
017cf080 WVS |
849 | /* |
850 | * We only stop the watchdog if we received the magic character | |
7e192b9c WVS |
851 | * or if WDIOF_MAGICCLOSE is not set. If nowayout was set then |
852 | * watchdog_stop will fail. | |
017cf080 | 853 | */ |
fcf95670 HP |
854 | if (!test_bit(WDOG_ACTIVE, &wdd->status)) |
855 | err = 0; | |
b4ffb190 | 856 | else if (test_and_clear_bit(_WDOG_ALLOW_RELEASE, &wd_data->status) || |
fcf95670 | 857 | !(wdd->info->options & WDIOF_MAGICCLOSE)) |
017cf080 | 858 | err = watchdog_stop(wdd); |
43316044 | 859 | |
017cf080 | 860 | /* If the watchdog was not stopped, send a keepalive ping */ |
234445b4 | 861 | if (err < 0) { |
0254e953 | 862 | pr_crit("watchdog%d: watchdog did not stop!\n", wdd->id); |
43316044 WVS |
863 | watchdog_ping(wdd); |
864 | } | |
865 | ||
ee142889 | 866 | watchdog_update_worker(wdd); |
664a3923 | 867 | |
43316044 | 868 | /* make sure that /dev/watchdog can be re-opened */ |
b4ffb190 | 869 | clear_bit(_WDOG_DEV_OPEN, &wd_data->status); |
e907df32 | 870 | |
b4ffb190 | 871 | done: |
d1ed3ba4 | 872 | running = wdd && watchdog_hw_running(wdd); |
b4ffb190 | 873 | mutex_unlock(&wd_data->lock); |
ee142889 GR |
874 | /* |
875 | * Allow the owner module to be unloaded again unless the watchdog | |
876 | * is still running. If the watchdog is still running, it can not | |
877 | * be stopped, and its driver must not be unloaded. | |
878 | */ | |
d1ed3ba4 GR |
879 | if (!running) { |
880 | module_put(wd_data->cdev.owner); | |
ee142889 GR |
881 | kref_put(&wd_data->kref, watchdog_core_data_release); |
882 | } | |
43316044 WVS |
883 | return 0; |
884 | } | |
885 | ||
886 | static const struct file_operations watchdog_fops = { | |
887 | .owner = THIS_MODULE, | |
888 | .write = watchdog_write, | |
2fa03560 | 889 | .unlocked_ioctl = watchdog_ioctl, |
43316044 WVS |
890 | .open = watchdog_open, |
891 | .release = watchdog_release, | |
892 | }; | |
893 | ||
894 | static struct miscdevice watchdog_miscdev = { | |
895 | .minor = WATCHDOG_MINOR, | |
896 | .name = "watchdog", | |
897 | .fops = &watchdog_fops, | |
898 | }; | |
899 | ||
900 | /* | |
32ecc639 | 901 | * watchdog_cdev_register: register watchdog character device |
bc794ac3 | 902 | * @wdd: watchdog device |
32ecc639 | 903 | * @devno: character device number |
43316044 | 904 | * |
32ecc639 | 905 | * Register a watchdog character device including handling the legacy |
45f5fed3 AC |
906 | * /dev/watchdog node. /dev/watchdog is actually a miscdevice and |
907 | * thus we set it up like that. | |
43316044 WVS |
908 | */ |
909 | ||
32ecc639 | 910 | static int watchdog_cdev_register(struct watchdog_device *wdd, dev_t devno) |
43316044 | 911 | { |
b4ffb190 | 912 | struct watchdog_core_data *wd_data; |
32ecc639 | 913 | int err; |
45f5fed3 | 914 | |
b4ffb190 GR |
915 | wd_data = kzalloc(sizeof(struct watchdog_core_data), GFP_KERNEL); |
916 | if (!wd_data) | |
917 | return -ENOMEM; | |
918 | kref_init(&wd_data->kref); | |
919 | mutex_init(&wd_data->lock); | |
920 | ||
921 | wd_data->wdd = wdd; | |
922 | wdd->wd_data = wd_data; | |
923 | ||
664a3923 GR |
924 | if (!watchdog_wq) |
925 | return -ENODEV; | |
926 | ||
927 | INIT_DELAYED_WORK(&wd_data->work, watchdog_ping_work); | |
928 | ||
bc794ac3 | 929 | if (wdd->id == 0) { |
b4ffb190 | 930 | old_wd_data = wd_data; |
bc794ac3 | 931 | watchdog_miscdev.parent = wdd->parent; |
45f5fed3 AC |
932 | err = misc_register(&watchdog_miscdev); |
933 | if (err != 0) { | |
934 | pr_err("%s: cannot register miscdev on minor=%d (err=%d).\n", | |
bc794ac3 | 935 | wdd->info->identity, WATCHDOG_MINOR, err); |
45f5fed3 AC |
936 | if (err == -EBUSY) |
937 | pr_err("%s: a legacy watchdog module is probably present.\n", | |
bc794ac3 | 938 | wdd->info->identity); |
b4ffb190 GR |
939 | old_wd_data = NULL; |
940 | kfree(wd_data); | |
45f5fed3 AC |
941 | return err; |
942 | } | |
43316044 WVS |
943 | } |
944 | ||
45f5fed3 | 945 | /* Fill in the data structures */ |
b4ffb190 GR |
946 | cdev_init(&wd_data->cdev, &watchdog_fops); |
947 | wd_data->cdev.owner = wdd->ops->owner; | |
45f5fed3 AC |
948 | |
949 | /* Add the device */ | |
b4ffb190 | 950 | err = cdev_add(&wd_data->cdev, devno, 1); |
45f5fed3 AC |
951 | if (err) { |
952 | pr_err("watchdog%d unable to add device %d:%d\n", | |
bc794ac3 GR |
953 | wdd->id, MAJOR(watchdog_devt), wdd->id); |
954 | if (wdd->id == 0) { | |
45f5fed3 | 955 | misc_deregister(&watchdog_miscdev); |
b4ffb190 GR |
956 | old_wd_data = NULL; |
957 | kref_put(&wd_data->kref, watchdog_core_data_release); | |
45f5fed3 | 958 | } |
ee142889 | 959 | return err; |
43316044 | 960 | } |
ee142889 | 961 | |
15013ad8 GR |
962 | /* Record time of most recent heartbeat as 'just before now'. */ |
963 | wd_data->last_hw_keepalive = jiffies - 1; | |
964 | ||
ee142889 GR |
965 | /* |
966 | * If the watchdog is running, prevent its driver from being unloaded, | |
967 | * and schedule an immediate ping. | |
968 | */ | |
969 | if (watchdog_hw_running(wdd)) { | |
914d65f3 GR |
970 | __module_get(wdd->ops->owner); |
971 | kref_get(&wd_data->kref); | |
972 | if (handle_boot_enabled) | |
2501b015 | 973 | queue_delayed_work(watchdog_wq, &wd_data->work, 0); |
914d65f3 | 974 | else |
2501b015 | 975 | pr_info("watchdog%d running and kernel based pre-userspace handler disabled\n", |
914d65f3 | 976 | wdd->id); |
ee142889 GR |
977 | } |
978 | ||
979 | return 0; | |
43316044 WVS |
980 | } |
981 | ||
982 | /* | |
32ecc639 | 983 | * watchdog_cdev_unregister: unregister watchdog character device |
43316044 WVS |
984 | * @watchdog: watchdog device |
985 | * | |
32ecc639 GR |
986 | * Unregister watchdog character device and if needed the legacy |
987 | * /dev/watchdog device. | |
43316044 WVS |
988 | */ |
989 | ||
32ecc639 | 990 | static void watchdog_cdev_unregister(struct watchdog_device *wdd) |
43316044 | 991 | { |
b4ffb190 | 992 | struct watchdog_core_data *wd_data = wdd->wd_data; |
e907df32 | 993 | |
b4ffb190 | 994 | cdev_del(&wd_data->cdev); |
bc794ac3 | 995 | if (wdd->id == 0) { |
45f5fed3 | 996 | misc_deregister(&watchdog_miscdev); |
b4ffb190 | 997 | old_wd_data = NULL; |
43316044 | 998 | } |
b4ffb190 GR |
999 | |
1000 | mutex_lock(&wd_data->lock); | |
1001 | wd_data->wdd = NULL; | |
1002 | wdd->wd_data = NULL; | |
1003 | mutex_unlock(&wd_data->lock); | |
1004 | ||
bb292ac1 GR |
1005 | if (watchdog_active(wdd) && |
1006 | test_bit(WDOG_STOP_ON_UNREGISTER, &wdd->status)) { | |
1007 | watchdog_stop(wdd); | |
1008 | } | |
1009 | ||
664a3923 GR |
1010 | cancel_delayed_work_sync(&wd_data->work); |
1011 | ||
b4ffb190 | 1012 | kref_put(&wd_data->kref, watchdog_core_data_release); |
43316044 | 1013 | } |
45f5fed3 | 1014 | |
906d7a5c PA |
1015 | static struct class watchdog_class = { |
1016 | .name = "watchdog", | |
1017 | .owner = THIS_MODULE, | |
33b71126 | 1018 | .dev_groups = wdt_groups, |
906d7a5c PA |
1019 | }; |
1020 | ||
44ea3942 AS |
1021 | static int watchdog_reboot_notifier(struct notifier_block *nb, |
1022 | unsigned long code, void *data) | |
1023 | { | |
1024 | struct watchdog_device *wdd; | |
1025 | ||
1026 | wdd = container_of(nb, struct watchdog_device, reboot_nb); | |
1027 | if (code == SYS_DOWN || code == SYS_HALT) { | |
1028 | if (watchdog_active(wdd)) { | |
1029 | int ret; | |
1030 | ||
1031 | ret = wdd->ops->stop(wdd); | |
1032 | if (ret) | |
1033 | return NOTIFY_BAD; | |
1034 | } | |
1035 | } | |
1036 | ||
1037 | return NOTIFY_DONE; | |
1038 | } | |
1039 | ||
32ecc639 GR |
1040 | /* |
1041 | * watchdog_dev_register: register a watchdog device | |
1042 | * @wdd: watchdog device | |
1043 | * | |
1044 | * Register a watchdog device including handling the legacy | |
1045 | * /dev/watchdog node. /dev/watchdog is actually a miscdevice and | |
1046 | * thus we set it up like that. | |
1047 | */ | |
1048 | ||
1049 | int watchdog_dev_register(struct watchdog_device *wdd) | |
1050 | { | |
1051 | struct device *dev; | |
1052 | dev_t devno; | |
1053 | int ret; | |
1054 | ||
1055 | devno = MKDEV(MAJOR(watchdog_devt), wdd->id); | |
1056 | ||
1057 | ret = watchdog_cdev_register(wdd, devno); | |
1058 | if (ret) | |
1059 | return ret; | |
1060 | ||
faa58475 GR |
1061 | dev = device_create_with_groups(&watchdog_class, wdd->parent, |
1062 | devno, wdd, wdd->groups, | |
1063 | "watchdog%d", wdd->id); | |
32ecc639 GR |
1064 | if (IS_ERR(dev)) { |
1065 | watchdog_cdev_unregister(wdd); | |
1066 | return PTR_ERR(dev); | |
1067 | } | |
32ecc639 | 1068 | |
ff84136c VZ |
1069 | ret = watchdog_register_pretimeout(wdd); |
1070 | if (ret) { | |
1071 | device_destroy(&watchdog_class, devno); | |
1072 | watchdog_cdev_unregister(wdd); | |
44ea3942 AS |
1073 | return ret; |
1074 | } | |
1075 | ||
1076 | if (test_bit(WDOG_STOP_ON_REBOOT, &wdd->status)) { | |
1077 | wdd->reboot_nb.notifier_call = watchdog_reboot_notifier; | |
1078 | ||
1079 | ret = devm_register_reboot_notifier(dev, &wdd->reboot_nb); | |
1080 | if (ret) { | |
1081 | pr_err("watchdog%d: Cannot register reboot notifier (%d)\n", | |
1082 | wdd->id, ret); | |
1083 | watchdog_dev_unregister(wdd); | |
1084 | } | |
ff84136c VZ |
1085 | } |
1086 | ||
32ecc639 GR |
1087 | return ret; |
1088 | } | |
1089 | ||
1090 | /* | |
1091 | * watchdog_dev_unregister: unregister a watchdog device | |
1092 | * @watchdog: watchdog device | |
1093 | * | |
1094 | * Unregister watchdog device and if needed the legacy | |
1095 | * /dev/watchdog device. | |
1096 | */ | |
1097 | ||
1098 | void watchdog_dev_unregister(struct watchdog_device *wdd) | |
1099 | { | |
ff84136c | 1100 | watchdog_unregister_pretimeout(wdd); |
0254e953 | 1101 | device_destroy(&watchdog_class, wdd->wd_data->cdev.dev); |
b4ffb190 | 1102 | watchdog_cdev_unregister(wdd); |
32ecc639 GR |
1103 | } |
1104 | ||
45f5fed3 AC |
1105 | /* |
1106 | * watchdog_dev_init: init dev part of watchdog core | |
1107 | * | |
1108 | * Allocate a range of chardev nodes to use for watchdog devices | |
1109 | */ | |
1110 | ||
32ecc639 | 1111 | int __init watchdog_dev_init(void) |
45f5fed3 | 1112 | { |
906d7a5c PA |
1113 | int err; |
1114 | ||
664a3923 GR |
1115 | watchdog_wq = alloc_workqueue("watchdogd", |
1116 | WQ_HIGHPRI | WQ_MEM_RECLAIM, 0); | |
1117 | if (!watchdog_wq) { | |
1118 | pr_err("Failed to create watchdog workqueue\n"); | |
1119 | return -ENOMEM; | |
1120 | } | |
1121 | ||
906d7a5c PA |
1122 | err = class_register(&watchdog_class); |
1123 | if (err < 0) { | |
1124 | pr_err("couldn't register class\n"); | |
138913cb | 1125 | goto err_register; |
906d7a5c PA |
1126 | } |
1127 | ||
1128 | err = alloc_chrdev_region(&watchdog_devt, 0, MAX_DOGS, "watchdog"); | |
1129 | if (err < 0) { | |
45f5fed3 | 1130 | pr_err("watchdog: unable to allocate char dev region\n"); |
138913cb | 1131 | goto err_alloc; |
906d7a5c PA |
1132 | } |
1133 | ||
32ecc639 | 1134 | return 0; |
138913cb WY |
1135 | |
1136 | err_alloc: | |
1137 | class_unregister(&watchdog_class); | |
1138 | err_register: | |
1139 | destroy_workqueue(watchdog_wq); | |
1140 | return err; | |
45f5fed3 AC |
1141 | } |
1142 | ||
1143 | /* | |
1144 | * watchdog_dev_exit: exit dev part of watchdog core | |
1145 | * | |
1146 | * Release the range of chardev nodes used for watchdog devices | |
1147 | */ | |
1148 | ||
1149 | void __exit watchdog_dev_exit(void) | |
1150 | { | |
1151 | unregister_chrdev_region(watchdog_devt, MAX_DOGS); | |
906d7a5c | 1152 | class_unregister(&watchdog_class); |
664a3923 | 1153 | destroy_workqueue(watchdog_wq); |
45f5fed3 | 1154 | } |
2501b015 SR |
1155 | |
1156 | module_param(handle_boot_enabled, bool, 0444); | |
1157 | MODULE_PARM_DESC(handle_boot_enabled, | |
1158 | "Watchdog core auto-updates boot enabled watchdogs before userspace takes over (default=" | |
1159 | __MODULE_STRING(IS_ENABLED(CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED)) ")"); |